src/gen/gensurf.c

#ifndef lint
static const char RCSid[] = "$Id: gensurf.c,v 2.30 2024/12/10 17:22:39 greg Exp $";
#endif
/*
 *  gensurf.c - program to generate functional surfaces
 *
 *      Parametric functions x(s,t), y(s,t) and z(s,t)
 *  specify the surface, which is tesselated into an m by n
 *  array of paired triangles.
 *      The surface normal is defined by the right hand
 *  rule applied to (s,t).
 *
 *      4/3/87
 *
 *      4/16/02 Added conditional vertex output
 */

#include  "standard.h"

#include  "paths.h"
#include  "resolu.h"
#include  "rterror.h"
#include  "calcomp.h"

char  XNAME[] =         "X`SYS";                /* x function name */
char  YNAME[] =         "Y`SYS";                /* y function name */
char  ZNAME[] =         "Z`SYS";                /* z function name */

char  VNAME[] =         "valid";                /* valid vertex name */

#define  ABS(x)         ((x)>=0 ? (x) : -(x))

#define  ZEROVECT(v)    (DOT(v,v) <= FTINY*FTINY)

#define  pvect(p)       printf(vformat, (p)[0], (p)[1], (p)[2])

char  vformat[] = "%18.12g %18.12g %18.12g\n";
char  tsargs[] = "4 surf_dx surf_dy surf_dz surf.cal";
char  texname[] = "Phong";

int  smooth = 0;                /* apply smoothing? */
int  objout = 0;                /* output .OBJ format? */
int  rev = 0;                   /* invert normal directions? */

char  *modname, *surfname;

                                /* recorded data flags */
#define  HASBORDER      01
#define  TRIPLETS       02
                                /* a data structure */
struct {
        int     flags;                  /* data type */
        short   m, n;                   /* number of s and t values */
        RREAL   *data;                  /* the data itself, s major sort */
} datarec;                      /* our recorded data */

/* XXX this is redundant with rt/noise3.c, should go to a library */
double  l_hermite(), l_bezier(), l_bspline(), l_dataval();

typedef struct {
        int  valid;     /* point is valid (vertex number) */
        int  nvalid;    /* normal is valid (normal number) */
        FVECT  p;       /* vertex position */
        FVECT  n;       /* average normal */
        RREAL  uv[2];   /* (u,v) position */
} POINT;

int  nverts = 0;                /* vertex output count */
int  nnorms = 0;                /* normal output count */

void loaddata(char *file, int m, int n, int pointsize);
double l_dataval(char *nam);
void putobjrow(POINT *rp, int n);
void putobjvert(POINT *p);
void putsquare(POINT *p0, POINT *p1, POINT *p2, POINT *p3);
void comprow(double s, POINT *row, int siz);
void compnorms(POINT *r0, POINT *r1, POINT *r2, int siz);
int norminterp(FVECT resmat[4], POINT *p0, POINT *p1, POINT *p2, POINT *p3);


int
main(int argc, char *argv[])
{
        POINT  *row0, *row1, *row2, *rp;
        int  i, j, m, n;
        char  stmp[256];

        esupport |= E_VARIABLE|E_FUNCTION|E_RCONST;
        esupport &= ~(E_OUTCHAN|E_INCHAN);
        varset("PI", ':', PI);
        funset("hermite", 5, ':', l_hermite);
        funset("bezier", 5, ':', l_bezier);
        funset("bspline", 5, ':', l_bspline);

        if (argc < 8)
                goto userror;

        for (i = 8; i < argc; i++)
                if (!strcmp(argv[i], "-e"))
                        scompile(argv[++i], NULL, 0);
                else if (!strcmp(argv[i], "-f")) {
                        char  *fpath = getpath(argv[++i], getrlibpath(), 0);
                        if (fpath == NULL) {
                                fprintf(stderr, "%s: cannot find file '%s'\n",
                                                argv[0], argv[i]);
                                quit(1);
                        }
                        fcompile(fpath);
                } else if (!strcmp(argv[i], "-s"))
                        smooth++;
                else if (!strcmp(argv[i], "-o"))
                        objout++;
                else if (!strcmp(argv[i], "-i"))
                        rev = 1;
                else
                        goto userror;

        modname = argv[1];
        surfname = argv[2];
        m = eval(argv[6]) + .5;
        n = eval(argv[7]) + .5;
        if (m <= 0 || n <= 0)
                goto userror;
        if (!strcmp(argv[5], "-") || access(argv[5], 4) == 0) { /* file? */
                funset(ZNAME, 2, ':', l_dataval);
                if (!strcmp(argv[5],argv[3]) && !strcmp(argv[5],argv[4])) {
                        loaddata(argv[5], m, n, 3);
                        funset(XNAME, 2, ':', l_dataval);
                        funset(YNAME, 2, ':', l_dataval);
                } else {
                        loaddata(argv[5], m, n, 1);
                        sprintf(stmp, "%s(s,t)=%s;", XNAME, argv[3]);
                        scompile(stmp, NULL, 0);
                        sprintf(stmp, "%s(s,t)=%s;", YNAME, argv[4]);
                        scompile(stmp, NULL, 0);
                }
        } else {
                sprintf(stmp, "%s(s,t)=%s;", XNAME, argv[3]);
                scompile(stmp, NULL, 0);
                sprintf(stmp, "%s(s,t)=%s;", YNAME, argv[4]);
                scompile(stmp, NULL, 0);
                sprintf(stmp, "%s(s,t)=%s;", ZNAME, argv[5]);
                scompile(stmp, NULL, 0);
        }
        row0 = (POINT *)malloc((n+3)*sizeof(POINT));
        row1 = (POINT *)malloc((n+3)*sizeof(POINT));
        row2 = (POINT *)malloc((n+3)*sizeof(POINT));
        if (row0 == NULL || row1 == NULL || row2 == NULL) {
                fprintf(stderr, "%s: out of memory\n", argv[0]);
                quit(1);
        }
        row0++; row1++; row2++;
                                                /* print header */
        fputs("# ", stdout);
        printargs(argc, argv, stdout);
        eclock = 1;
                                                /* initialize */
        comprow(-1.0/m, row0, n);
        comprow(0.0, row1, n);
        comprow(1.0/m, row2, n);
        compnorms(row0, row1, row2, n);
        if (objout) {
                printf("\nusemtl %s\n\n", modname);
                printf("o %s\n\n", surfname);
                putobjrow(row1, n);
        }
                                                /* for each row */
        for (i = 0; i < m; i++) {
                                                /* compute next row */
                rp = row0;
                row0 = row1;
                row1 = row2;
                row2 = rp;
                comprow((double)(i+2)/m, row2, n);
                compnorms(row0, row1, row2, n);
                if (objout)
                        putobjrow(row1, n);

                for (j = 0; j < n; j++) {
                        int  orient = (j & 1);
                                                        /* put polygons */
                        if (!(row0[j].valid && row1[j+1].valid))
                                orient = 1;
                        else if (!(row1[j].valid && row0[j+1].valid))
                                orient = 0;
                        if (orient)
                                putsquare(&row0[j], &row1[j],
                                                &row0[j+1], &row1[j+1]);
                        else
                                putsquare(&row1[j], &row1[j+1],
                                                &row0[j], &row0[j+1]);
                }
        }

        return 0;

userror:
        fprintf(stderr, "Usage: %s material name ", argv[0]);
        fprintf(stderr, "x(s,t) y(s,t) z(s,t) m n [-s][-o][-e expr][-f file]\n");
        return 1;
}


void
loaddata(               /* load point data from file */
        char  *file,
        int  m,
        int  n,
        int  pointsize
)
{
        FILE  *fp;
        char  word[64];
        int  size;
        RREAL  *dp;

        datarec.flags = HASBORDER;              /* assume border values */
        datarec.m = m+1;
        datarec.n = n+1;
        size = datarec.m*datarec.n*pointsize;
        if (pointsize == 3)
                datarec.flags |= TRIPLETS;
        dp = (RREAL *)malloc(size*sizeof(RREAL));
        if ((datarec.data = dp) == NULL) {
                fputs("Out of memory\n", stderr);
                exit(1);
        }
        if (!strcmp(file, "-")) {
                file = "<stdin>";
                fp = stdin;
        } else if ((fp = fopen(file, "r")) == NULL) {
                fputs(file, stderr);
                fputs(": cannot open\n", stderr);
                exit(1);
        }
        while (size > 0 && fgetword(word, sizeof(word), fp) != NULL) {
                if (!isflt(word)) {
                        fprintf(stderr, "%s: garbled data value: %s\n",
                                        file, word);
                        exit(1);
                }
                *dp++ = atof(word);
                size--;
        }
        if (size == (m+n+1)*pointsize) {        /* no border after all */
                dp = (RREAL *)realloc(datarec.data,
                                m*n*pointsize*sizeof(RREAL));
                if (dp != NULL)
                        datarec.data = dp;
                datarec.flags &= ~HASBORDER;
                datarec.m = m;
                datarec.n = n;
                size = 0;
        }
        if (datarec.m < 2 || datarec.n < 2 || size != 0 ||
                        fgetword(word, sizeof(word), fp) != NULL) {
                fputs(file, stderr);
                fputs(": bad number of data points\n", stderr);
                exit(1);
        }
        fclose(fp);
}


double
l_dataval(                              /* return recorded data value */
        char  *nam
)
{
        double  u, v;
        int  i, j;
        RREAL  *dp;
        double  d00, d01, d10, d11;
                                                /* compute coordinates */
        u = argument(1); v = argument(2);
        if (datarec.flags & HASBORDER) {
                i = u *= datarec.m-1;
                j = v *= datarec.n-1;
        } else {
                i = u = u*datarec.m - .5;
                j = v = v*datarec.n - .5;
        }
        if (i < 0) i = 0;
        else if (i > datarec.m-2) i = datarec.m-2;
        if (j < 0) j = 0;
        else if (j > datarec.n-2) j = datarec.n-2;
                                                /* compute value */
        if (datarec.flags & TRIPLETS) {
                dp = datarec.data + 3*(j*datarec.m + i);
                if (nam == ZNAME)
                        dp += 2;
                else if (nam == YNAME)
                        dp++;
                d00 = dp[0]; d01 = dp[3];
                dp += 3*datarec.m;
                d10 = dp[0]; d11 = dp[3];
        } else {
                dp = datarec.data + j*datarec.m + i;
                d00 = dp[0]; d01 = dp[1];
                dp += datarec.m;
                d10 = dp[0]; d11 = dp[1];
        }
                                                /* bilinear interpolation */
        return((j+1-v)*((i+1-u)*d00+(u-i)*d01)+(v-j)*((i+1-u)*d10+(u-i)*d11));
}


void
putobjrow(                      /* output vertex row to .OBJ */
        POINT  *rp,
        int  n
)
{
        static FVECT  prevNorm;

        for ( ; n-- >= 0; rp++) {
                if (!rp->valid)
                        continue;
                fputs("v ", stdout);
                pvect(rp->p);
                rp->valid = ++nverts;
                printf("\tvt %.9g %.9g\n", rp->uv[0], rp->uv[1]);
                if (!smooth || ZEROVECT(rp->n))
                        rp->nvalid = 0;
                else if (VABSEQ(rp->n, prevNorm))
                        rp->nvalid = nnorms;
                else {
                        printf("\tvn %.9g %.9g %.9g\n",
                                        rp->n[0], rp->n[1], rp->n[2]);
                        rp->nvalid = ++nnorms;
                        VCOPY(prevNorm, rp->n);
                }
        }
}


void
putobjvert(             /* put out OBJ vertex index triplet */
        POINT *p
)
{
        int     pti = p->valid ? p->valid-nverts-1 : 0;
        int     ni = p->nvalid ? p->nvalid-nnorms-1 : 0;
        
        printf(" %d/%d/%d", pti, pti, ni);
}


void
putsquare(              /* put out a square */
        POINT *p0,
        POINT *p1,
        POINT *p2,
        POINT *p3
)
{
        static int  nout = 0;
        FVECT  norm[4];
        int  axis;
        FVECT  v1, v2, vc1, vc2;
        int  ok1, ok2;

        if (rev) {                      /* reverse normals? */
                POINT  *pt = p1; p1 = p2; p2 = pt;
        }
                                        /* compute exact normals */
        ok1 = (p0->valid && p1->valid && p2->valid);
        if (ok1) {
                VSUB(v1, p1->p, p0->p);
                VSUB(v2, p2->p, p0->p);
                fcross(vc1, v1, v2);
                ok1 = (normalize(vc1) != 0.0);
        }
        ok2 = (p1->valid && p2->valid && p3->valid);
        if (ok2) {
                VSUB(v1, p2->p, p3->p);
                VSUB(v2, p1->p, p3->p);
                fcross(vc2, v1, v2);
                ok2 = (normalize(vc2) != 0.0);
        }
        if (!(ok1 | ok2))
                return;
        if (objout) {                   /* output .OBJ faces */
                if (ok1 & ok2 && fdot(vc1,vc2) >= 1.0-FTINY*FTINY) {
                        putc('f', stdout);
                        putobjvert(p0); putobjvert(p1);
                        putobjvert(p3); putobjvert(p2);
                        putc('\n', stdout);
                        return;
                }
                if (ok1) {
                        putc('f', stdout);
                        putobjvert(p0); putobjvert(p1); putobjvert(p2);
                        putc('\n', stdout);
                }
                if (ok2) {
                        putc('f', stdout);
                        putobjvert(p2); putobjvert(p1); putobjvert(p3);
                        putc('\n', stdout);
                }
                return;
        }
                                        /* compute normal interpolation */
        axis = norminterp(norm, p0, p1, p2, p3);

                                        /* put out quadrilateral? */
        if (ok1 & ok2 && fdot(vc1,vc2) >= 1.0-FTINY*FTINY) {
                printf("\n%s ", modname);
                if (axis != -1) {
                        printf("texfunc %s\n%s\n", texname, tsargs);
                        printf("0\n13\t%d\n", axis);
                        pvect(norm[0]);
                        pvect(norm[1]);
                        pvect(norm[2]);
                        fvsum(v1, norm[3], vc1, -0.5);
                        fvsum(v1, v1, vc2, -0.5);
                        pvect(v1);
                        printf("\n%s ", texname);
                }
                printf("polygon %s.%d\n", surfname, ++nout);
                printf("0\n0\n12\n");
                pvect(p0->p);
                pvect(p1->p);
                pvect(p3->p);
                pvect(p2->p);
                return;
        }
                                        /* put out triangles? */
        if (ok1) {
                printf("\n%s ", modname);
                if (axis != -1) {
                        printf("texfunc %s\n%s\n", texname, tsargs);
                        printf("0\n13\t%d\n", axis);
                        pvect(norm[0]);
                        pvect(norm[1]);
                        pvect(norm[2]);
                        fvsum(v1, norm[3], vc1, -1.0);
                        pvect(v1);
                        printf("\n%s ", texname);
                }
                printf("polygon %s.%d\n", surfname, ++nout);
                printf("0\n0\n9\n");
                pvect(p0->p);
                pvect(p1->p);
                pvect(p2->p);
        }
        if (ok2) {
                printf("\n%s ", modname);
                if (axis != -1) {
                        printf("texfunc %s\n%s\n", texname, tsargs);
                        printf("0\n13\t%d\n", axis);
                        pvect(norm[0]);
                        pvect(norm[1]);
                        pvect(norm[2]);
                        fvsum(v2, norm[3], vc2, -1.0);
                        pvect(v2);
                        printf("\n%s ", texname);
                }
                printf("polygon %s.%d\n", surfname, ++nout);
                printf("0\n0\n9\n");
                pvect(p2->p);
                pvect(p1->p);
                pvect(p3->p);
        }
}


void
comprow(                        /* compute row of values */
        double  s,
        POINT  *row,
        int  siz
)
{
        double  st[2];
        int  end;
        int  checkvalid;
        int  i;
        
        if (smooth) {
                i = -1;                 /* compute one past each end */
                end = siz+1;
        } else {
                if (s < -FTINY || s > 1.0+FTINY)
                        return;
                i = 0;
                end = siz;
        }
        st[0] = s;
        checkvalid = (fundefined(VNAME) == 2);
        while (i <= end) {
                st[1] = (double)i/siz;
                if (checkvalid && funvalue(VNAME, 2, st) <= 0.0) {
                        row[i].valid = 0;
                        row[i].p[0] = row[i].p[1] = row[i].p[2] = 0.0;
                        row[i].uv[0] = row[i].uv[1] = 0.0;
                } else {
                        row[i].valid = 1;
                        row[i].p[0] = funvalue(XNAME, 2, st);
                        row[i].p[1] = funvalue(YNAME, 2, st);
                        row[i].p[2] = funvalue(ZNAME, 2, st);
                        row[i].uv[0] = st[0];
                        row[i].uv[1] = st[1];
                }
                i++;
        }
}


void
compnorms(              /* compute row of averaged normals */
        POINT  *r0,
        POINT  *r1,
        POINT  *r2,
        int  siz
)
{
        FVECT  v1, v2;

        if (!smooth)                    /* not needed if no smoothing */
                return;
                                        /* compute row 1 normals */
        while (siz-- >= 0) {
                if (!r1[0].valid)
                        goto skip;
                if (!r0[0].valid) {
                        if (!r2[0].valid) {
                                r1[0].n[0] = r1[0].n[1] = r1[0].n[2] = 0.0;
                                goto skip;
                        }
                        fvsum(v1, r2[0].p, r1[0].p, -1.0);
                } else if (!r2[0].valid)
                        fvsum(v1, r1[0].p, r0[0].p, -1.0);
                else
                        fvsum(v1, r2[0].p, r0[0].p, -1.0);
                if (!r1[-1].valid) {
                        if (!r1[1].valid) {
                                r1[0].n[0] = r1[0].n[1] = r1[0].n[2] = 0.0;
                                goto skip;
                        }
                        fvsum(v2, r1[1].p, r1[0].p, -1.0);
                } else if (!r1[1].valid)
                        fvsum(v2, r1[0].p, r1[-1].p, -1.0);
                else
                        fvsum(v2, r1[1].p, r1[-1].p, -1.0);
                if (rev)
                        fcross(r1[0].n, v2, v1);
                else
                        fcross(r1[0].n, v1, v2);
                normalize(r1[0].n);
        skip:
                r0++; r1++; r2++;
        }
}


int
norminterp(     /* compute normal interpolation */
        FVECT  resmat[4],
        POINT  *p0,
        POINT  *p1,
        POINT  *p2,
        POINT  *p3
)
{
#define u  ((ax+1)%3)
#define v  ((ax+2)%3)

        int  ax;
        MAT4  eqnmat;
        FVECT  v1;
        int  i, j;

        if (!smooth)                    /* no interpolation if no smoothing */
                return(-1);
                                        /* find dominant axis */
        VCOPY(v1, p0->n);
        fvsum(v1, v1, p1->n, 1.0);
        fvsum(v1, v1, p2->n, 1.0);
        fvsum(v1, v1, p3->n, 1.0);
        ax = ABS(v1[0]) > ABS(v1[1]) ? 0 : 1;
        ax = ABS(v1[ax]) > ABS(v1[2]) ? ax : 2;
                                        /* assign equation matrix */
        eqnmat[0][0] = p0->p[u]*p0->p[v];
        eqnmat[0][1] = p0->p[u];
        eqnmat[0][2] = p0->p[v];
        eqnmat[0][3] = 1.0;
        eqnmat[1][0] = p1->p[u]*p1->p[v];
        eqnmat[1][1] = p1->p[u];
        eqnmat[1][2] = p1->p[v];
        eqnmat[1][3] = 1.0;
        eqnmat[2][0] = p2->p[u]*p2->p[v];
        eqnmat[2][1] = p2->p[u];
        eqnmat[2][2] = p2->p[v];
        eqnmat[2][3] = 1.0;
        eqnmat[3][0] = p3->p[u]*p3->p[v];
        eqnmat[3][1] = p3->p[u];
        eqnmat[3][2] = p3->p[v];
        eqnmat[3][3] = 1.0;
                                        /* invert matrix (solve system) */
        if (!invmat4(eqnmat, eqnmat))
                return(-1);                     /* no solution */
                                        /* compute result matrix */
        for (j = 0; j < 4; j++)
                for (i = 0; i < 3; i++)
                        resmat[j][i] =  eqnmat[j][0]*p0->n[i] +
                                        eqnmat[j][1]*p1->n[i] +
                                        eqnmat[j][2]*p2->n[i] +
                                        eqnmat[j][3]*p3->n[i];
        return(ax);

#undef u
#undef v
}


double
l_hermite(char *nm)
{
        double  t;
        
        t = argument(5);
        return( argument(1)*((2.0*t-3.0)*t*t+1.0) +
                argument(2)*(-2.0*t+3.0)*t*t +
                argument(3)*((t-2.0)*t+1.0)*t +
                argument(4)*(t-1.0)*t*t );
}


double
l_bezier(char *nm)
{
        double  t;

        t = argument(5);
        return( argument(1) * (1.+t*(-3.+t*(3.-t))) +
                argument(2) * 3.*t*(1.+t*(-2.+t)) +
                argument(3) * 3.*t*t*(1.-t) +
                argument(4) * t*t*t );
}


double
l_bspline(char *nm)
{
        double  t;

        t = argument(5);
        return( argument(1) * (1./6.+t*(-1./2.+t*(1./2.-1./6.*t))) +
                argument(2) * (2./3.+t*t*(-1.+1./2.*t)) +
                argument(3) * (1./6.+t*(1./2.+t*(1./2.-1./2.*t))) +
                argument(4) * (1./6.*t*t*t) );
}
Revision:	2.31
Committed:	Tue Jan 21 01:56:27 2025 UTC (4 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.30:	+12 -2 lines
Log Message:	feat(gensurf): Added gensurf -i option to reverse surface normals
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.31	static const char RCSid[] = "$Id: gensurf.c,v 2.30 2024/12/10 17:22:39 greg Exp $";
3	greg	1.1	#endif
4	greg	1.2	/*
5	greg	1.1	* gensurf.c - program to generate functional surfaces
6			*
7			* Parametric functions x(s,t), y(s,t) and z(s,t)
8			* specify the surface, which is tesselated into an m by n
9			* array of paired triangles.
10			* The surface normal is defined by the right hand
11			* rule applied to (s,t).
12			*
13			* 4/3/87
14	greg	2.6	*
15			* 4/16/02 Added conditional vertex output
16	greg	1.1	*/
17
18	greg	2.14	#include "standard.h"
19	schorsch	2.15
20			#include "paths.h"
21	greg	2.16	#include "resolu.h"
22			#include "rterror.h"
23	schorsch	2.13	#include "calcomp.h"
24	greg	1.1
25	greg	2.6	char XNAME[] = "X`SYS"; /* x function name */
26			char YNAME[] = "Y`SYS"; /* y function name */
27			char ZNAME[] = "Z`SYS"; /* z function name */
28
29			char VNAME[] = "valid"; /* valid vertex name */
30	greg	1.1
31	greg	1.4	#define ABS(x) ((x)>=0 ? (x) : -(x))
32
33	greg	2.9	#define ZEROVECT(v) (DOT(v,v) <= FTINY*FTINY)
34
35	greg	1.3	#define pvect(p) printf(vformat, (p)[0], (p)[1], (p)[2])
36	greg	1.1
37	greg	2.18	char vformat[] = "%18.12g %18.12g %18.12g\n";
38	greg	2.19	char tsargs[] = "4 surf_dx surf_dy surf_dz surf.cal";
39	greg	1.3	char texname[] = "Phong";
40	greg	1.1
41	greg	1.3	int smooth = 0; /* apply smoothing? */
42	greg	2.7	int objout = 0; /* output .OBJ format? */
43	greg	2.31	int rev = 0; /* invert normal directions? */
44	greg	1.1
45	greg	1.3	char modname, surfname;
46	greg	1.1
47	greg	2.2	/* recorded data flags */
48			#define HASBORDER 01
49			#define TRIPLETS 02
50			/* a data structure */
51			struct {
52			int flags; /* data type */
53			short m, n; /* number of s and t values */
54	schorsch	2.11	RREAL data; / the data itself, s major sort */
55	greg	2.2	} datarec; /* our recorded data */
56	greg	1.3
57	schorsch	2.13	/* XXX this is redundant with rt/noise3.c, should go to a library */
58	greg	2.2	double l_hermite(), l_bezier(), l_bspline(), l_dataval();
59
60	greg	1.3	typedef struct {
61	greg	2.7	int valid; /* point is valid (vertex number) */
62	greg	2.29	int nvalid; /* normal is valid (normal number) */
63	greg	1.3	FVECT p; /* vertex position */
64			FVECT n; /* average normal */
65	schorsch	2.11	RREAL uv[2]; /* (u,v) position */
66	greg	1.3	} POINT;
67
68	greg	2.23	int nverts = 0; /* vertex output count */
69			int nnorms = 0; /* normal output count */
70	greg	1.3
71	schorsch	2.13	void loaddata(char *file, int m, int n, int pointsize);
72			double l_dataval(char *nam);
73			void putobjrow(POINT *rp, int n);
74	greg	2.23	void putobjvert(POINT *p);
75	schorsch	2.13	void putsquare(POINT p0, POINT p1, POINT p2, POINT p3);
76			void comprow(double s, POINT *row, int siz);
77			void compnorms(POINT r0, POINT r1, POINT *r2, int siz);
78			int norminterp(FVECT resmat[4], POINT p0, POINT p1, POINT p2, POINT p3);
79
80
81			int
82	greg	2.28	main(int argc, char *argv[])
83	greg	1.1	{
84	greg	1.3	POINT row0, row1, row2, rp;
85	greg	1.1	int i, j, m, n;
86			char stmp[256];
87
88	greg	2.24	esupport \|= E_VARIABLE\|E_FUNCTION\|E_RCONST;
89			esupport &= ~(E_OUTCHAN\|E_INCHAN);
90	greg	1.13	varset("PI", ':', PI);
91	greg	1.14	funset("hermite", 5, ':', l_hermite);
92			funset("bezier", 5, ':', l_bezier);
93			funset("bspline", 5, ':', l_bspline);
94	greg	1.1
95			if (argc < 8)
96			goto userror;
97
98			for (i = 8; i < argc; i++)
99			if (!strcmp(argv[i], "-e"))
100	greg	1.10	scompile(argv[++i], NULL, 0);
101	greg	2.25	else if (!strcmp(argv[i], "-f")) {
102			char *fpath = getpath(argv[++i], getrlibpath(), 0);
103			if (fpath == NULL) {
104			fprintf(stderr, "%s: cannot find file '%s'\n",
105			argv[0], argv[i]);
106			quit(1);
107			}
108			fcompile(fpath);
109			} else if (!strcmp(argv[i], "-s"))
110	greg	1.3	smooth++;
111	greg	2.7	else if (!strcmp(argv[i], "-o"))
112			objout++;
113	greg	2.31	else if (!strcmp(argv[i], "-i"))
114			rev = 1;
115	greg	1.1	else
116			goto userror;
117
118	greg	1.3	modname = argv[1];
119			surfname = argv[2];
120	greg	2.26	m = eval(argv[6]) + .5;
121			n = eval(argv[7]) + .5;
122	greg	1.1	if (m <= 0 \|\| n <= 0)
123			goto userror;
124	greg	2.2	if (!strcmp(argv[5], "-") \|\| access(argv[5], 4) == 0) { /* file? */
125			funset(ZNAME, 2, ':', l_dataval);
126			if (!strcmp(argv[5],argv[3]) && !strcmp(argv[5],argv[4])) {
127			loaddata(argv[5], m, n, 3);
128			funset(XNAME, 2, ':', l_dataval);
129			funset(YNAME, 2, ':', l_dataval);
130			} else {
131			loaddata(argv[5], m, n, 1);
132			sprintf(stmp, "%s(s,t)=%s;", XNAME, argv[3]);
133			scompile(stmp, NULL, 0);
134			sprintf(stmp, "%s(s,t)=%s;", YNAME, argv[4]);
135			scompile(stmp, NULL, 0);
136			}
137			} else {
138			sprintf(stmp, "%s(s,t)=%s;", XNAME, argv[3]);
139			scompile(stmp, NULL, 0);
140			sprintf(stmp, "%s(s,t)=%s;", YNAME, argv[4]);
141			scompile(stmp, NULL, 0);
142			sprintf(stmp, "%s(s,t)=%s;", ZNAME, argv[5]);
143			scompile(stmp, NULL, 0);
144			}
145	greg	1.4	row0 = (POINT )malloc((n+3)sizeof(POINT));
146			row1 = (POINT )malloc((n+3)sizeof(POINT));
147			row2 = (POINT )malloc((n+3)sizeof(POINT));
148	greg	1.3	if (row0 == NULL \|\| row1 == NULL \|\| row2 == NULL) {
149	greg	1.1	fprintf(stderr, "%s: out of memory\n", argv[0]);
150			quit(1);
151			}
152	greg	1.4	row0++; row1++; row2++;
153	greg	1.3	/* print header */
154	greg	2.16	fputs("# ", stdout);
155			printargs(argc, argv, stdout);
156	greg	2.30	eclock = 1;
157	greg	1.4	/* initialize */
158			comprow(-1.0/m, row0, n);
159	greg	1.3	comprow(0.0, row1, n);
160			comprow(1.0/m, row2, n);
161	greg	1.4	compnorms(row0, row1, row2, n);
162	greg	2.8	if (objout) {
163			printf("\nusemtl %s\n\n", modname);
164	greg	2.28	printf("o %s\n\n", surfname);
165	greg	2.7	putobjrow(row1, n);
166	greg	2.8	}
167	greg	1.3	/* for each row */
168	greg	1.1	for (i = 0; i < m; i++) {
169			/* compute next row */
170	greg	1.3	rp = row0;
171	greg	1.1	row0 = row1;
172	greg	1.3	row1 = row2;
173			row2 = rp;
174	greg	1.4	comprow((double)(i+2)/m, row2, n);
175			compnorms(row0, row1, row2, n);
176	greg	2.7	if (objout)
177			putobjrow(row1, n);
178	greg	1.1
179			for (j = 0; j < n; j++) {
180	greg	2.6	int orient = (j & 1);
181	greg	1.3	/* put polygons */
182	greg	2.7	if (!(row0[j].valid && row1[j+1].valid))
183	greg	2.6	orient = 1;
184	greg	2.7	else if (!(row1[j].valid && row0[j+1].valid))
185	greg	2.6	orient = 0;
186			if (orient)
187	greg	1.3	putsquare(&row0[j], &row1[j],
188			&row0[j+1], &row1[j+1]);
189			else
190			putsquare(&row1[j], &row1[j+1],
191			&row0[j], &row0[j+1]);
192	greg	1.1	}
193			}
194
195	schorsch	2.13	return 0;
196	greg	1.1
197			userror:
198			fprintf(stderr, "Usage: %s material name ", argv[0]);
199	greg	2.17	fprintf(stderr, "x(s,t) y(s,t) z(s,t) m n [-s][-o][-e expr][-f file]\n");
200	schorsch	2.13	return 1;
201	greg	2.2	}
202
203
204	schorsch	2.13	void
205			loaddata( /* load point data from file */
206			char *file,
207			int m,
208			int n,
209			int pointsize
210			)
211	greg	2.2	{
212			FILE *fp;
213			char word[64];
214	greg	2.22	int size;
215			RREAL *dp;
216	greg	2.2
217			datarec.flags = HASBORDER; /* assume border values */
218	greg	2.3	datarec.m = m+1;
219			datarec.n = n+1;
220			size = datarec.mdatarec.npointsize;
221	greg	2.2	if (pointsize == 3)
222			datarec.flags \|= TRIPLETS;
223	schorsch	2.11	dp = (RREAL )malloc(sizesizeof(RREAL));
224	greg	2.2	if ((datarec.data = dp) == NULL) {
225			fputs("Out of memory\n", stderr);
226			exit(1);
227			}
228			if (!strcmp(file, "-")) {
229			file = "<stdin>";
230			fp = stdin;
231			} else if ((fp = fopen(file, "r")) == NULL) {
232			fputs(file, stderr);
233			fputs(": cannot open\n", stderr);
234			exit(1);
235			}
236			while (size > 0 && fgetword(word, sizeof(word), fp) != NULL) {
237			if (!isflt(word)) {
238			fprintf(stderr, "%s: garbled data value: %s\n",
239			file, word);
240			exit(1);
241			}
242			*dp++ = atof(word);
243			size--;
244			}
245			if (size == (m+n+1)pointsize) { / no border after all */
246	greg	2.20	dp = (RREAL *)realloc(datarec.data,
247	schorsch	2.11	mnpointsize*sizeof(RREAL));
248	greg	2.2	if (dp != NULL)
249			datarec.data = dp;
250			datarec.flags &= ~HASBORDER;
251	greg	2.3	datarec.m = m;
252			datarec.n = n;
253	greg	2.2	size = 0;
254			}
255	greg	2.3	if (datarec.m < 2 \|\| datarec.n < 2 \|\| size != 0 \|\|
256			fgetword(word, sizeof(word), fp) != NULL) {
257	greg	2.2	fputs(file, stderr);
258			fputs(": bad number of data points\n", stderr);
259			exit(1);
260			}
261			fclose(fp);
262			}
263
264
265			double
266	schorsch	2.13	l_dataval( /* return recorded data value */
267			char *nam
268			)
269	greg	2.2	{
270			double u, v;
271	greg	2.22	int i, j;
272			RREAL *dp;
273	greg	2.2	double d00, d01, d10, d11;
274			/* compute coordinates */
275			u = argument(1); v = argument(2);
276			if (datarec.flags & HASBORDER) {
277	greg	2.3	i = u *= datarec.m-1;
278			j = v *= datarec.n-1;
279	greg	2.2	} else {
280	greg	2.3	i = u = u*datarec.m - .5;
281			j = v = v*datarec.n - .5;
282	greg	2.2	}
283			if (i < 0) i = 0;
284			else if (i > datarec.m-2) i = datarec.m-2;
285			if (j < 0) j = 0;
286			else if (j > datarec.n-2) j = datarec.n-2;
287			/* compute value */
288			if (datarec.flags & TRIPLETS) {
289	greg	2.3	dp = datarec.data + 3(jdatarec.m + i);
290			if (nam == ZNAME)
291			dp += 2;
292			else if (nam == YNAME)
293	greg	2.2	dp++;
294			d00 = dp[0]; d01 = dp[3];
295	greg	2.3	dp += 3*datarec.m;
296	greg	2.2	d10 = dp[0]; d11 = dp[3];
297			} else {
298	greg	2.3	dp = datarec.data + j*datarec.m + i;
299	greg	2.2	d00 = dp[0]; d01 = dp[1];
300	greg	2.3	dp += datarec.m;
301	greg	2.2	d10 = dp[0]; d11 = dp[1];
302			}
303			/* bilinear interpolation */
304			return((j+1-v)((i+1-u)d00+(u-i)d01)+(v-j)((i+1-u)d10+(u-i)d11));
305	greg	1.1	}
306
307
308	schorsch	2.13	void
309			putobjrow( /* output vertex row to .OBJ */
310	greg	2.22	POINT *rp,
311	schorsch	2.13	int n
312			)
313	greg	2.7	{
314	greg	2.29	static FVECT prevNorm;
315
316	greg	2.7	for ( ; n-- >= 0; rp++) {
317			if (!rp->valid)
318			continue;
319			fputs("v ", stdout);
320	greg	2.9	pvect(rp->p);
321	greg	2.29	rp->valid = ++nverts;
322			printf("\tvt %.9g %.9g\n", rp->uv[0], rp->uv[1]);
323			if (!smooth \|\| ZEROVECT(rp->n))
324			rp->nvalid = 0;
325			else if (VABSEQ(rp->n, prevNorm))
326			rp->nvalid = nnorms;
327			else {
328	greg	2.7	printf("\tvn %.9g %.9g %.9g\n",
329			rp->n[0], rp->n[1], rp->n[2]);
330	greg	2.21	rp->nvalid = ++nnorms;
331	greg	2.29	VCOPY(prevNorm, rp->n);
332			}
333	greg	2.7	}
334			}
335
336
337	schorsch	2.13	void
338	greg	2.23	putobjvert( /* put out OBJ vertex index triplet */
339			POINT *p
340			)
341			{
342			int pti = p->valid ? p->valid-nverts-1 : 0;
343			int ni = p->nvalid ? p->nvalid-nnorms-1 : 0;
344
345			printf(" %d/%d/%d", pti, pti, ni);
346			}
347
348
349			void
350	schorsch	2.13	putsquare( /* put out a square */
351			POINT *p0,
352			POINT *p1,
353			POINT *p2,
354			POINT *p3
355			)
356	greg	1.3	{
357			static int nout = 0;
358			FVECT norm[4];
359			int axis;
360			FVECT v1, v2, vc1, vc2;
361			int ok1, ok2;
362	greg	2.31
363			if (rev) { /* reverse normals? */
364			POINT *pt = p1; p1 = p2; p2 = pt;
365			}
366	greg	1.3	/* compute exact normals */
367	greg	2.7	ok1 = (p0->valid && p1->valid && p2->valid);
368	greg	2.6	if (ok1) {
369	greg	2.9	VSUB(v1, p1->p, p0->p);
370			VSUB(v2, p2->p, p0->p);
371	greg	2.6	fcross(vc1, v1, v2);
372			ok1 = (normalize(vc1) != 0.0);
373			}
374	greg	2.7	ok2 = (p1->valid && p2->valid && p3->valid);
375	greg	2.6	if (ok2) {
376	greg	2.9	VSUB(v1, p2->p, p3->p);
377			VSUB(v2, p1->p, p3->p);
378	greg	2.6	fcross(vc2, v1, v2);
379			ok2 = (normalize(vc2) != 0.0);
380			}
381	greg	1.3	if (!(ok1 \| ok2))
382			return;
383	greg	2.7	if (objout) { /* output .OBJ faces */
384			if (ok1 & ok2 && fdot(vc1,vc2) >= 1.0-FTINY*FTINY) {
385	greg	2.23	putc('f', stdout);
386			putobjvert(p0); putobjvert(p1);
387			putobjvert(p3); putobjvert(p2);
388			putc('\n', stdout);
389	greg	2.7	return;
390			}
391	greg	2.23	if (ok1) {
392			putc('f', stdout);
393			putobjvert(p0); putobjvert(p1); putobjvert(p2);
394			putc('\n', stdout);
395			}
396			if (ok2) {
397			putc('f', stdout);
398			putobjvert(p2); putobjvert(p1); putobjvert(p3);
399			putc('\n', stdout);
400			}
401	greg	2.7	return;
402			}
403	greg	1.3	/* compute normal interpolation */
404			axis = norminterp(norm, p0, p1, p2, p3);
405
406			/* put out quadrilateral? */
407			if (ok1 & ok2 && fdot(vc1,vc2) >= 1.0-FTINY*FTINY) {
408			printf("\n%s ", modname);
409			if (axis != -1) {
410	greg	2.19	printf("texfunc %s\n%s\n", texname, tsargs);
411	greg	1.3	printf("0\n13\t%d\n", axis);
412			pvect(norm[0]);
413			pvect(norm[1]);
414			pvect(norm[2]);
415			fvsum(v1, norm[3], vc1, -0.5);
416			fvsum(v1, v1, vc2, -0.5);
417			pvect(v1);
418			printf("\n%s ", texname);
419			}
420			printf("polygon %s.%d\n", surfname, ++nout);
421			printf("0\n0\n12\n");
422			pvect(p0->p);
423			pvect(p1->p);
424			pvect(p3->p);
425			pvect(p2->p);
426			return;
427			}
428			/* put out triangles? */
429			if (ok1) {
430			printf("\n%s ", modname);
431			if (axis != -1) {
432	greg	2.19	printf("texfunc %s\n%s\n", texname, tsargs);
433	greg	1.3	printf("0\n13\t%d\n", axis);
434			pvect(norm[0]);
435			pvect(norm[1]);
436			pvect(norm[2]);
437			fvsum(v1, norm[3], vc1, -1.0);
438			pvect(v1);
439			printf("\n%s ", texname);
440			}
441			printf("polygon %s.%d\n", surfname, ++nout);
442			printf("0\n0\n9\n");
443			pvect(p0->p);
444			pvect(p1->p);
445			pvect(p2->p);
446			}
447			if (ok2) {
448			printf("\n%s ", modname);
449			if (axis != -1) {
450	greg	2.19	printf("texfunc %s\n%s\n", texname, tsargs);
451	greg	1.3	printf("0\n13\t%d\n", axis);
452			pvect(norm[0]);
453			pvect(norm[1]);
454			pvect(norm[2]);
455			fvsum(v2, norm[3], vc2, -1.0);
456			pvect(v2);
457			printf("\n%s ", texname);
458			}
459			printf("polygon %s.%d\n", surfname, ++nout);
460			printf("0\n0\n9\n");
461			pvect(p2->p);
462			pvect(p1->p);
463			pvect(p3->p);
464			}
465			}
466
467
468	schorsch	2.13	void
469			comprow( /* compute row of values */
470			double s,
471	greg	2.22	POINT *row,
472	schorsch	2.13	int siz
473			)
474	greg	1.1	{
475	greg	1.4	double st[2];
476	greg	1.8	int end;
477	greg	2.6	int checkvalid;
478	greg	2.22	int i;
479	greg	1.8
480			if (smooth) {
481			i = -1; /* compute one past each end */
482			end = siz+1;
483			} else {
484			if (s < -FTINY \|\| s > 1.0+FTINY)
485			return;
486			i = 0;
487			end = siz;
488			}
489	greg	1.1	st[0] = s;
490	greg	2.6	checkvalid = (fundefined(VNAME) == 2);
491	greg	1.8	while (i <= end) {
492	greg	1.4	st[1] = (double)i/siz;
493	greg	2.6	if (checkvalid && funvalue(VNAME, 2, st) <= 0.0) {
494			row[i].valid = 0;
495			row[i].p[0] = row[i].p[1] = row[i].p[2] = 0.0;
496	greg	2.7	row[i].uv[0] = row[i].uv[1] = 0.0;
497	greg	2.6	} else {
498			row[i].valid = 1;
499			row[i].p[0] = funvalue(XNAME, 2, st);
500			row[i].p[1] = funvalue(YNAME, 2, st);
501			row[i].p[2] = funvalue(ZNAME, 2, st);
502	greg	2.7	row[i].uv[0] = st[0];
503			row[i].uv[1] = st[1];
504	greg	2.6	}
505	greg	1.8	i++;
506	greg	1.1	}
507	greg	1.3	}
508
509
510	schorsch	2.13	void
511			compnorms( /* compute row of averaged normals */
512	greg	2.22	POINT *r0,
513			POINT *r1,
514			POINT *r2,
515	schorsch	2.13	int siz
516			)
517	greg	1.3	{
518	greg	1.11	FVECT v1, v2;
519	greg	1.3
520			if (!smooth) /* not needed if no smoothing */
521			return;
522	greg	2.6	/* compute row 1 normals */
523	greg	1.4	while (siz-- >= 0) {
524	greg	2.6	if (!r1[0].valid)
525	greg	2.27	goto skip;
526	greg	2.6	if (!r0[0].valid) {
527			if (!r2[0].valid) {
528			r1[0].n[0] = r1[0].n[1] = r1[0].n[2] = 0.0;
529	greg	2.27	goto skip;
530	greg	2.6	}
531			fvsum(v1, r2[0].p, r1[0].p, -1.0);
532			} else if (!r2[0].valid)
533			fvsum(v1, r1[0].p, r0[0].p, -1.0);
534			else
535			fvsum(v1, r2[0].p, r0[0].p, -1.0);
536			if (!r1[-1].valid) {
537			if (!r1[1].valid) {
538			r1[0].n[0] = r1[0].n[1] = r1[0].n[2] = 0.0;
539	greg	2.27	goto skip;
540	greg	2.6	}
541			fvsum(v2, r1[1].p, r1[0].p, -1.0);
542			} else if (!r1[1].valid)
543			fvsum(v2, r1[0].p, r1[-1].p, -1.0);
544			else
545			fvsum(v2, r1[1].p, r1[-1].p, -1.0);
546	greg	2.31	if (rev)
547			fcross(r1[0].n, v2, v1);
548			else
549			fcross(r1[0].n, v1, v2);
550	greg	1.3	normalize(r1[0].n);
551	greg	2.27	skip:
552	greg	1.3	r0++; r1++; r2++;
553			}
554			}
555
556
557			int
558	schorsch	2.13	norminterp( /* compute normal interpolation */
559	greg	2.22	FVECT resmat[4],
560	schorsch	2.13	POINT *p0,
561			POINT *p1,
562			POINT *p2,
563			POINT *p3
564			)
565	greg	1.3	{
566			#define u ((ax+1)%3)
567			#define v ((ax+2)%3)
568
569	greg	2.22	int ax;
570	greg	1.12	MAT4 eqnmat;
571	greg	1.3	FVECT v1;
572	greg	2.22	int i, j;
573	greg	1.3
574			if (!smooth) /* no interpolation if no smoothing */
575			return(-1);
576			/* find dominant axis */
577			VCOPY(v1, p0->n);
578			fvsum(v1, v1, p1->n, 1.0);
579			fvsum(v1, v1, p2->n, 1.0);
580			fvsum(v1, v1, p3->n, 1.0);
581	greg	1.4	ax = ABS(v1[0]) > ABS(v1[1]) ? 0 : 1;
582			ax = ABS(v1[ax]) > ABS(v1[2]) ? ax : 2;
583	greg	1.3	/* assign equation matrix */
584			eqnmat[0][0] = p0->p[u]*p0->p[v];
585			eqnmat[0][1] = p0->p[u];
586			eqnmat[0][2] = p0->p[v];
587			eqnmat[0][3] = 1.0;
588			eqnmat[1][0] = p1->p[u]*p1->p[v];
589			eqnmat[1][1] = p1->p[u];
590			eqnmat[1][2] = p1->p[v];
591			eqnmat[1][3] = 1.0;
592			eqnmat[2][0] = p2->p[u]*p2->p[v];
593			eqnmat[2][1] = p2->p[u];
594			eqnmat[2][2] = p2->p[v];
595			eqnmat[2][3] = 1.0;
596			eqnmat[3][0] = p3->p[u]*p3->p[v];
597			eqnmat[3][1] = p3->p[u];
598			eqnmat[3][2] = p3->p[v];
599			eqnmat[3][3] = 1.0;
600			/* invert matrix (solve system) */
601	greg	2.5	if (!invmat4(eqnmat, eqnmat))
602	greg	1.3	return(-1); /* no solution */
603			/* compute result matrix */
604			for (j = 0; j < 4; j++)
605			for (i = 0; i < 3; i++)
606	greg	1.4	resmat[j][i] = eqnmat[j][0]*p0->n[i] +
607			eqnmat[j][1]*p1->n[i] +
608			eqnmat[j][2]*p2->n[i] +
609			eqnmat[j][3]*p3->n[i];
610	greg	1.3	return(ax);
611
612			#undef u
613			#undef v
614	greg	1.1	}
615
616
617			double
618	greg	2.12	l_hermite(char *nm)
619	greg	1.1	{
620			double t;
621
622			t = argument(5);
623			return( argument(1)((2.0t-3.0)tt+1.0) +
624			argument(2)(-2.0t+3.0)tt +
625			argument(3)((t-2.0)t+1.0)*t +
626			argument(4)(t-1.0)t*t );
627	greg	1.6	}
628
629
630			double
631	greg	2.12	l_bezier(char *nm)
632	greg	1.6	{
633			double t;
634
635			t = argument(5);
636			return( argument(1) * (1.+t(-3.+t(3.-t))) +
637			argument(2) * 3.t(1.+t*(-2.+t)) +
638			argument(3) * 3.tt*(1.-t) +
639			argument(4) * ttt );
640	greg	1.7	}
641
642
643			double
644	greg	2.12	l_bspline(char *nm)
645	greg	1.7	{
646			double t;
647
648			t = argument(5);
649			return( argument(1) * (1./6.+t(-1./2.+t(1./2.-1./6.*t))) +
650			argument(2) * (2./3.+tt(-1.+1./2.*t)) +
651			argument(3) * (1./6.+t(1./2.+t(1./2.-1./2.*t))) +
652			argument(4) * (1./6.tt*t) );
653	greg	1.1	}